Agent-based scenario models of invasion and movement of the orchard pest Rhagoletis pomonella (Diptera: Tephritidae) within the southern interior of British Columbia

The apple maggot, Rhagoletis pomonella, is an economically important pest of pome fruits in the United States and southern Canada. Presently, British Columbia's Okanagan Region is the only significant commercial apple-producing region in North America that remains free of it. This is likely to change soon, as R. pomonella is well established within certain counties in adjacent Washington State and has been difficult to manage. Extensive sampling and control efforts have been undertaken since its arrival in Washington in the late 1970‘s. The resulting data provided the foundation for spatially explicit agent-based models (ABM), used to evaluate fly movement and establishment under different management schemes within the comparable Okanagan region. By following simple movement rules, these ABMs simulate the apple maggot spread across the Okanagan region, interacting with both the landscape and management practices. The simulations yield maps expressing risk of infestation under various management and land change scenarios. Preliminary findings will be presented, as well as the results of validation tests against Washington data. To our knowledge, ABMs have not previously been used to explore scenarios of spread of an insect pest into a new region. Ultimately, the resulting ABMs will be used to inform management and survey efforts as R. pomonella establishes in the southern interior of British Columbia.